How shall we sing, etc. The Psalmist puts a lofty and magnanimous answer into the mouth of the Lord's people to their insolent reproach, which is this, that they abstained from their songs, as from their legal sacrifices, because the land where they now were was polluted. The Chaldeans thought the Jews were bound down permanently to this place of their exile; the Psalmist, when he calls it a foreign land, suggests that it was but the place of their temporary stay. But the main idea is, that Chaldea was not worthy of the honor of having God's praises sung in it. No doubt the children of God wherever they have lived have always been strangers and foreigners in the world, but the land of Canaan was the sacred rest provided for them, and the Psalmist well describes them as being foreigners and sojourners when they were in other climes. He would in this way have them to be always ready and prepared for their return, tacitly enforcing what Jeremiah had prophesied, when, in order to prevent them from forgetting their native country, he had definitely foretold the time during which their exile should last, (Jeremiah 25:11; Jeremiah 29:10.) He would in the meantime animate them to constancy, and have them not to coalesce with the Babylonians through motives of fear. In our own day under the Papacy, great as the danger may be to which the faithful expose themselves by not conforming to the example around them, the Holy Spirit makes use of such a barrier as this to separate them from sinful compliances. To those, whether Frenchmen, Englishmen, or Italians, who love and practice the true religion, even their native country is a foreign clime when they live under that tyranny. And yet there is a distinction between us and God's ancient people, for at that time the worship of God was confined to one place, but now he has his Temple wherever two or three are met together in Christ's name, if they separate themselves from all idolatrous profession, and maintain purity of divine worship. The Psalmist by the language which he employs would by no means put down every attempt on their part to celebrate God's praises. He rather exhorts them under their affliction to wait with patience till the liberty of publicly worshipping God was restored, saying' upon the matter -- We have been bereft of our Temple and sacrifices, we wander as exiles in a polluted land, and what remains but that in remembrance of our outcast state we should sigh and groan for the promised deliverance.

How shall we sing the Lord's song - The song designed to celebrate his praise; that is, appropriate to the worship of Yahweh.
In a strange land - Far from our home; far from the temple; exiles; captives: how can we find spirit in such circumstances to sing? How can we do that which would be indicative of what we do not feel, and cannot feel - joy and happiness! The idea is not that those psalms or songs would be profaned by being sung there, or that there would be anything improper in itself in singing them, but that it would be misplaced and incongruous to sing them in their circumstances. It would be doing violence to their own feelings; their feelings would not allow them to do it. There are states of mind when the language of joy is appropriate and natural; there are states where the heart is so sad that it cannot sing.

How shall we sing the Lord's song - איך נשיר eich! nashir; O, we sing! Who does not hear the deep sigh in the strongly guttural sound of the original איך eich! wrung, as it were, from the bottom of the heart? Can We, in this state of slavery, - We, exiles, from our country, We, stripped of all our property, - We, reduced to contempt by our strong enemy, - We, deprived of our religious privileges, - We, insulted by our oppressors, - We, in the land of heathens, - We sing, or be mirthful in these circumstances? No: God does not expect it; man should not wish it; and it is base in our enemies to require it.

How shall we sing the Lord's song in a strange land? This is the answer returned by the Jews to the above request or demand; it may be, particularly, by the Levites, whose business it was to sing these songs: so the Targum,
"immediately the Levites said, how shall we sing the hymns of the Lord in a strange land?''
This they said, not merely on account of their unsuitable circumstances, being in distress and affliction, and so not disposed for such work; nor as if unlawful to them, being forbidden: for, though sacrifices were not to be offered but at Jerusalem, yet songs of praise might be sung elsewhere, on proper occasions, as David did, Psalm 18:49; but as wondering at their insolence, and complaining of their cruelty and inhumanity, thus to insult them and jeer at them: or rather, because it was "the Lord's song" they required, and so sacred, and not to be sung in any place, or at any time, and in any company; which would be but casting pearls before swine, and giving that which was holy to dogs, Matthew 7:6; or it may be they required this to be done in one of their temples, and to their idols, just as these songs were sung in the temple at Jerusalem, and to the honour of Jehovah; and therefore they refused to do it: for it may be rendered, or however interpreted, "in the land of a strange god" (c); as it is by Aben Ezra, Kimchi, and Ben Melech: they required them to sing with mirth and joy, which they could not do in their present case; see Psalm 137:2.
(c) "in terra peregina, sc. Dei", Muis, Michaelis.

The Lord's - Those songs which were appointed by God to be sung only in his service.